Date: Thu, 19 Feb 2004 15:56:15 +0100 From: Marian Durkovic <md@bts.sk> To: freebsd-net@freebsd.org Subject: Solution: TX performance problems with 3Com 905C cards Message-ID: <20040219145615.GB80953@us.svf.stuba.sk> In-Reply-To: <20040217154148.GA85482@us.svf.stuba.sk> References: <20040216170733.GA37519@us.svf.stuba.sk> <20040217154148.GA85482@us.svf.stuba.sk>
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Hi all,
the performance problem seems to disappear, when the hardware checksuming
for TX direction is disabled (RX hw checksuming still on).
Here are the results:
otherbox -> box with 3c905C:
Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s
l409600000 34.80 2.89 94.1488 1134.2671 100000 2873.19 34615.1
1409600000 34.82 1.21 94.1173 2707.3675 281392 8082.24 232492.5
box with 3c905C -> otherbox:
Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s
l409600000 34.91 1.20 93.8721 2737.7209 282783 8101.03 236261.3
1409600000 34.90 1.67 93.8939 1962.4189 100000 2865.41 59888.3
With kind regards,
M.
> I'm experiencing some performance issues with 3Com 905C cards @ FreeBSD 4.8
> When running nttcp tests with other servers, the result is:
>
> otherbox -> box with 3c905
>
> Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s
> l409600000 34.80 2.96 94.1489 1105.1982 100000 2873.20 33728.0
> 1409600000 34.82 1.18 94.1175 2773.2828 281323 8080.27 238094.6
>
> box with 3c905 -> otherbox
>
> Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s
> l409600000 38.86 1.18 84.3323 2766.3223 282788 7277.88 238733.7
> 1409600000 38.85 1.56 84.3524 2100.2557 100000 2574.23 64094.7
>
> The above data shows that 3c905C is able to receive data at full wire speed
> of FastEthernet since the value corresponds to its theoretical maximum.
> However, when 3c905C is transmitting data, the rate drops to 84 Mbps.
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